Method and apparatus for analyte measurement test time

ABSTRACT

A disposable biosensor test strip is provided that includes a plurality of penetrating members. Each penetrating member is associated with a capillary chamber that has a depth suitable for capillary flow of blood and holds a volume of less than about 1.0 μl of the blood sample. A working electrode and a counter or reference electrode are disposed within the capillary chamber. A reagent is proximal to or in contact with at least the working electrode. The reagent includes an enzyme and a mediator. The reagent reacts with glucose to produce an electroactive reaction product. A blood sample, containing glucose, is applied into the capillary chamber. The capillary chamber directs capillary flow of the blood sample into contact with the reagent to cause the blood sample to at least partially solubilize or hydrate the reagent. The blood sample is detected in the capillary chamber. The electroactive reaction product is electro-oxidized or electro-reduced at the working electrode. Within 10 seconds after detecting, a determination is made of glucose concentration and a readout of the measurement is provided. The glucose determination is made by correlating the electro-oxidized or electro-reduced electroactive reaction product to the concentration of glucose in the blood sample.

CROSS-REFERENCE TO RELATED CASES

This application is a continuation-in-part of U.S. Ser. No. 11/813,014filed Dec. 30, 2005, which is a filing under §3.71 of PCT/US05/47480filed Dec. 30, 2005, which application claims the benefit of U.S. Ser.No. 60/640,879 filed Dec. 30, 2004, all of which applications are fullyincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Technical Field

The technical field relates to analyte measurement, and morespecifically, the amount of time it takes to complete an analytemeasurement.

2. Background Art

Lancing devices are known in the medical health-care products industryfor piercing the skin to produce blood for analysis. Typically, a dropof blood for this type of analysis is obtained by making a smallincision in the fingertip, creating a small wound, which generates asmall blood droplet on the surface of the skin.

Early methods of lancing included piercing or slicing the skin with aneedle or razor. Current methods utilize lancing devices that contain amultitude of spring, cam and mass actuators to drive the lancet. Theseinclude cantilever springs, diaphragms, coil springs, as well as gravityplumbs used to drive the lancet. The device may be held against the skinand mechanically triggered to ballistically launch the lancet.Unfortunately, the pain associated with each lancing event using knowntechnology discourages patients from testing. In addition to vibratorystimulation of the skin as the driver impacts the end of a launcherstop, known spring based devices have the possibility of firing lancetsthat harmonically oscillate against the patient tissue, causing multiplestrikes due to recoil. This recoil and multiple strikes of the lancet isone major impediment to patient compliance with a structured glucosemonitoring regime.

Success rate generally encompasses the probability of producing a bloodsample with one lancing action, which is sufficient in volume to performthe desired analytical test. The blood may appear spontaneously at thesurface of the skin, or may be “milked” from the wound. Milkinggenerally involves pressing the side of the digit, or in proximity ofthe wound to express the blood to the surface. In traditional methods,the blood droplet produced by the lancing action must reach the surfaceof the skin to be viable for testing.

When using existing methods, blood often flows from the cut bloodvessels but is then trapped below the surface of the skin, forming ahematoma. In other instances, a wound is created, but no blood flowsfrom the wound. In either case, the lancing process cannot be combinedwith the sample acquisition and testing step. Spontaneous blood dropletgeneration with current mechanical launching system varies betweenlauncher types but on average it is about 50% of lancet strikes, whichwould be spontaneous. Otherwise milking is required to yield blood.Mechanical launchers are unlikely to provide the means for integratedsample acquisition and testing if one out of every two strikes does notyield a spontaneous blood sample.

Many diabetic patients (insulin dependent) are required to self-test forblood glucose levels five to six times daily. The large number of stepsrequired in traditional methods of glucose testing ranging from lancing,to milking of blood, applying blood to the test strip, and getting themeasurements from the test strip discourages many diabetic patients fromtesting their blood glucose levels as often as recommended. Tightcontrol of plasma glucose through frequent testing is thereforemandatory for disease management. The pain associated with each lancingevent further discourages patients from testing. Additionally, the woundchannel left on the patient by known systems may also be of a size thatdiscourages those who are active with their hands or who are worriedabout healing of those wound channels from testing their glucose levels.

Another problem frequently encountered by patients who must use lancingequipment to obtain and analyze blood samples is the amount of manualdexterity and hand-eye coordination required to properly operate thelancing and sample testing equipment due to retinopathies andneuropathies particularly, severe in elderly diabetic patients. Forthose patients, operating existing lancet and sample testing equipmentcan be a challenge. Once a blood droplet is created, that droplet mustthen be guided into a receiving channel of a small test strip or thelike. If the sample placement on the strip is unsuccessful, repetitionof the entire procedure including re-lancing the skin to obtain a newblood droplet is necessary.

Early methods of using test strips required a relatively substantialvolume of blood to obtain an accurate glucose measurement. This largeblood requirement made the monitoring experience a painful one for theuser since the user may need to lance deeper than comfortable to obtainsufficient blood generation. Alternatively, if insufficient blood isspontaneously generated, the user may need to “milk” the wound tosqueeze enough blood to the skin surface. Neither method is desirable asthey take additional user effort and may be painful. The discomfort andinconvenience associated with such lancing events may deter a user fromtesting their blood glucose levels in a rigorous manner sufficient tocontrol their diabetes.

A further impediment to patient compliance is the amount of time ittakes for a user to obtain an analyte measurement using known devices.There are typically several devices in separate packaging that aretypically brought together to perform the testing. These multipledevices such as test strips, lancets, a meter, and/or a lancet launcherall increase the complexity and burden on a user.

There is a need to provide methods for reducing the total test time fora user to complete an analyte measurements using analyte measurementdevices.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a methodfor improving analyte measurement test time and convenience.

Another object of the present invention is to provide a method forimproving glucose measurement test time and convenience.

Yet another embodiment of the present invention is to provide a methodfor measuring an analyte with an analyte measurement device in less than10 seconds.

A further object of the present invention is to provide a method formeasuring analyte with an analyte measurement device that haspenetrating members, that is quick and does not require the user todirectly handle the penetrating members

Another object of the present invention is to provide a method formeasuring analyte with an analyte measurement device that haspenetrating members, that is quick and does not require the user toremove and dispose of the penetrating members from the analytemeasurement device.

Yet another object of the present invention is to provide a method formeasuring analyte with an analyte measurement device that haspenetrating members, that is quick and where the analyte measure deviceis ready for the next lancing event without having to dispose of theused penetrating member or a used analyte detecting member.

These and other objects of the present invention are achieved with adisposable biosensor test strip that includes a plurality of penetratingmembers. Each penetrating member is associated with a capillary chamberthat has a depth suitable for capillary flow of blood and holds a volumeof less than about 1.0 μl of the blood sample. A working electrode and acounter or reference electrode are disposed within the capillarychamber. A reagent is proximal to or in contact with at least theworking electrode. The reagent includes an enzyme and a mediator. Thereagent reacts with glucose to produce an electroactive reactionproduct. A blood sample, containing glucose, is applied into thecapillary chamber. The capillary chamber directs capillary flow of theblood sample into contact with the reagent to cause the blood sample toat least partially solubilize or hydrate the reagent. The blood sampleis detected in the capillary chamber. The electroactive reaction productis electro-oxidized or electro-reduced at the working electrode. Within10 seconds after detecting, a determination is made of glucoseconcentration and a readout of the measurement is provided. The glucosedetermination is made by correlating the electro-oxidized orelectro-reduced electroactive reaction product to the concentration ofglucose in the blood sample.

In another embodiment of the present invention, a disposable biosensortest strip and a plurality of penetrating members are provided. Eachpenetrating member is associated with a capillary chamber that has adepth suitable for capillary flow of blood and holds a volume of lessthan about 1.0 μl of the blood sample. A working electrode and a counteror reference electrode are disposed within the capillary chamber. Areagent is proximal to or in contact with at least the workingelectrode. The reagent includes an enzyme and a mediator and reacts withglucose to produce an electroactive reaction product. A blood samplecontaining glucose is applied into the capillary chamber. The capillarychamber directing capillary flow of the blood sample into contact withthe reagent to cause the blood sample to at least partially solubilizeor hydrate the reagent; The blood sample is detected in the capillarychamber and the electroactive reactive product is electrooxidized at theworking electrode. Within 10 seconds after the detecting step, a readoutof the glucose concentration in the blood sample is made. Thedetermination of glucose is made by correlating the electrooxidizedelectroactive reaction product to the concentration of glucose in theblood sample.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart illustrating one method of the present invention.

FIG. 2 illustrates an embodiment of a penetrating member driver that canused with the methods of the present invention.

FIGS. 3( a) and 3(b) illustrate embodiments of displacement and velocityprofiles, respectively, of a harmonic spring/mass powered driver thatcan be used with the methods of the present invention.

FIG. 3( c) illustrates an embodiment of a controlled displacementprofile that can be utilized with the methods of the present invention.

FIG. 3( d) illustrates an embodiment of a the controlled velocityprofile that can be used with the methods of the present invention.

FIG. 4 illustrates a feedback loop and a processor that can be used withthe methods of the present invention.

FIG. 5 illustrates a tissue penetration device, more specifically, alancing device and a controllable driver coupled to a tissue penetrationelement, that can be used with the methods of the present invention.

FIG. 6 illustrates the lancing device of FIG. 5 in more detail.

FIG. 7 is a partial sectional view of a disposable device that can beutilized with the methods of the present invention.

FIG. 8 is a full sectional view of the FIG. 7 disposable device.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

The present invention provides a solution for body fluid sampling.Specifically, some embodiments of the present invention provide improveddevices and methods for storing a sampling device. The invention may usea high density penetrating member design. It may use penetrating membersof smaller size, such as but not limited to diameter or length, thanthose of conventional penetrating members known in the art. The devicemay be used for multiple lancing events without having to remove adisposable from the device. The invention may provide improved sensingcapabilities. At least some of these and other objectives describedherein will be met by embodiments of the present invention.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention, as claimed. It may be notedthat, as used in the specification and the appended claims, the singularforms “a”, “an” and “the” include plural referents unless the contextclearly dictates otherwise. Thus, for example, reference to “a material”may include mixtures of materials, reference to “a chamber” may includemultiple chambers, and the like. References cited herein are herebyincorporated by reference in their entirety, except to the extent thatthey conflict with teachings explicitly set forth in this specification.

In this specification and in the claims which follow, reference will bemade to a number of terms which shall be defined to have the followingmeanings:

“Optional” or “optionally” means that the subsequently describedcircumstance may or may not occur, so that the description includesinstances where the circumstance occurs and instances where it does not.For example, if a device optionally contains a feature for analyzing ablood sample, this means that the analysis feature may or may not bepresent, and, thus, the description includes structures wherein a devicepossesses the analysis feature and structures wherein the analysisfeature is not present.

In one embodiment of the present invention, a method is provided fordoing an analyte measurement by a user using an analyte measurementdevice in three steps. In a first step, a penetrating member and unusedanalyte detecting member of the analyte measurement device are presentedinto an active position. In a second step, the penetrating member isfired to prick the skin and bring a fluid sample to theanalyte-detecting member. In a third step, the analyte level ismeasured. In one embodiment, these three steps occur in less than 10seconds. In another embodiment, these steps occur in less than 7seconds. The analyte level can be displayed to the use, and a value ofthe analyte level can be stored in or out of the analyte measurementdevice.

These three steps can be performed without the user directly handlingthe penetrating member to obtain a fresh penetrating member or load thepenetrating member, and/or without the user coding the analytemeasurement device. Blood is applied to an analyte detection memberduring lancing. Application of blood to an analyte detection memberduring lancing occurs without removal and disposal of penetratingmembers from the analyte measurement device. The three steps can beperformed without a separate step of apply blood to a analyte detectionmember after lancing. The second step can be performed without milking awound. The second step can be performed using at least one of apenetrating member driver selected from, spring based, electromechanicalbased, magnetic driver based, and nanomuscle based.

The second step can be performed with controlled velocity and depth ofpenetration, as more fully described hereafter. The analyte measurementdevice can be returned to a storage condition without having to disposeof a used penetrating member or used analyte detecting members. Theanalyte measurement device is ready for the next lancing event withouthaving to dispose of the used penetrating member or the used analytedetecting member. In one embodiment, a time from pressing an on buttonof the analyte measurement device to lancing and measuring the analytelevel is no more than 10 seconds.

From the moment the user thinks that it is time to do an analytemeasurement (and begins the test process, reaches for the analytemeasurement device, or initiates movement to begin the testing) to thetime that a reading appears, in one embodiment, the present inventiondesires to be 10 seconds or less.

The test time breaks down into smaller pieces. The user will desire todo a test and then grab their measurement kit. In some embodiments, theuser will take some action to turn on the analyte measurement device andtake some action to prepare it. The user would hold the analytemeasurement device to their skin and then first with some action by theuser. Thus so far, the user will turn on the analyte measurement device,prepare it, and fire it. This may be combined into one. The time ittakes is about 2 seconds to fire, 2 process to interact, and 4 secondsto get your readings.

A user right now will take about 20 seconds if certain steps areskipped. If the proper steps are taken then it takes a user about aminute. It is unlikely that a user may improve by a second or two if asecond person helps. The speed is based on someone with dexterity to dothings quickly. In one embodiment, the present invention provides atesting regime that removes much of the user variability and dexterityto testing.

In one embodiment of the present invention, the user does not need todispose of or handle waste materials after each testing event, the userdoes not need to put the lancer back in place, the via back in place, ormeter back in place. The present invention can offer a single analytemeasurement device. The present invention can allow a user to get theirreading and the put the analyte measurement device back down to wherethey had it. Whatever the user needs to do to return the analytemeasurement device to their normal state or storage state is the endpoint of the time measurement.

The present invention removes taking a strip out of a vial, putting astrip into a meter, disposing of the strip, eliminate the need to grab aseparate lancing device, eliminate the transfer step from a finger to atest strip.

The starting point for measuring may be when they open the carrying caseor grabbing the test strip vial (to begin a test process). This mayinvolve press the button or slide the slider to produce the test stripfrom the analyte measurement device. The step of physically preparingthe strip is removed. Some users will leave the meter in a carryingcase.

The present invention is the lower test time and the removal of certainsteps. The present invention provides a convenience factor. Even thoughsome steps will be reduced in time, the number of steps to reach areading is improved. The user may wait less, but there is no reductionin convenience. The absolute time is more of a benefit of reduced steps.Even the automatically dispensing test strip devices still have the stepof placing the strip and then removing it when done. There are noelimination of steps.

In the present invention, opening a latch or other trigger on theanalyte measurement device may be used to prepare the analytemeasurement device to have more device steps performed by fewer usersteps. A latch may be opened and this may allow the analyte measurementdevice to power up and advance for next lancing event.

FIG. 1 is a flow chart of one embodiment of a method of the presentinvention. The analyte measurement device may be turned on at step 2. Insome embodiments, the turn on at step 2 also performs the bringing of anunused penetrating member (and analyte detecting member as the case maybe) into position. Some embodiments of the present invention has anexplicit step 4 for bringing an unused penetrating member and analytedetecting member into position. Step 6 shows that the user may fire theanalyte measurement device by a variety of methods including but notlimited to pressing a button on the analyte measurement device. Thefiring will prick the skin and bring a blood sample into the analytemeasurement device. The user then waits to see a measurement at step 8.At step 9, the user replaces the analyte measurement device into itsstorage condition, perhaps in a carrying case or by simply placing itback where the user stores testing devices. As indicated by the phantomline, the user will proceed back to step 2 when time comes for the nextlancing event.

The present invention desires to complete the end-to-end testing processin less than 10 seconds. In some embodiments, the testing process iscompleted in less than 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20seconds. The present invention provides greater convenience byeliminating certain step but still arrive at the same end result ofobtaining an analyte measurement.

It should be understood that one way to view the present invention isthe number of steps performed by the user and the number of stepsperformed by the analyte measurement device. The present inventionshifts the number of steps performed by the user and minimizes thosesteps while increasing the number of steps performed by analytemeasurement device. Thus in one embodiment, the user may perform foursteps (turn on, activate new penetrating member/analyte detectingmember, pick skin, return meter to storage condition), the analytemeasurement device will perform additional steps not seen by the user(rotate cartridge to bring new penetrating member in position, obtainsample from skin prick, transfer sample to detecting member, store usedpenetrating member, store used analyte testing devices. The presentinvention involves removing some steps completely and shifting many ofthe steps into the analyte measurement device.

In another embodiment of the present invention, a method of analytemeasurement by a user uses an analyte measurement device in four steps.In the first step, a decision is made to test. In the second step, apenetrating member and unused analyte detecting member of the analytemeasurement device is presented into an active position. In the thirdstep, the penetrating member is fired to prick the skin and bring afluid sample to the analyte detecting member. In the fourth step, theanalyte level is measured. These four steps occur in no more than 1minute. In various embodiments, steps one through four occur in morethan, 30 seconds, 15 seconds, 10 seconds, and the like.

In another embodiment of the present invention, a method of analytemeasurement is performed with an analyte measurement device in foursteps. In a first step, a penetrating member and unused analytedetecting member of the analyte measurement device is presented into anactive position by rotating a disposabe device to align in an activeposition. Seals covering the penetrating member and analyte detectingmember are removed. In a second step, the penetrating member is fired toprick the skin using a driver to advance and retract from the skin tocreate a wound from which body fluid expresses. In a third step, a fluidsample is brought to the analyte detecting member by providing a samplecapture structure positioned to contact body fluid expressed from thewound. In a fourth step, the analyte levels are measured. In oneembodiment, these four steps occur in no more than 10 seconds. Invarious embodiments, these four steps are performed without the user,directly handling the penetrating member to obtain a fresh penetratingmember or load the penetrating member, or coding the analyte measurementdevice.

In one embodiment, the four steps are performed without a separate stepof apply blood to a analyte detection member after lancing. In anotherembodiment, the second and third steps are performed without milking awound.

The analyte level can be displayed to the use, and a value of theanalyte level can be stored in or out of the analyte measurement device.Blood is applied to an analyte detection member during lancing.Application of blood to an analyte detection member during lancingoccurs without removal and disposal of penetrating members from theanalyte measurement device.

In one embodiment, the second and third steps are performed using atleast one of a penetrating member driver selected from, spring based,electro-mechanical based, magnetic driver based, and nanomuscle based.In another embodiment, the third step is performed with controlledvelocity and depth of penetration.

The analyte measurement device can be returned to a storage conditionwithout having to dispose of a used penetrating member or used analytedetecting members. The analyte measurement device is ready for the nextlancing event without having to dispose of the used penetrating memberor the used analyte detecting member. In one embodiment, a time frompressing an on button of the analyte measurement device to lancing andmeasuring the analyte level is no more than 10 seconds. In anotherembodiment, there is no disposal of a used analyte detecting member anda used penetrating member after each lancing step. In anotherembodiment, the four steps are performed without a disposal or handlingof waste step.

The present invention may be used with a variety of differentpenetrating member drivers. It is contemplated that these penetratingmember drivers may be spring based, solenoid based, magnetic driverbased, nanomuscle based, or based on any other mechanism useful inmoving a penetrating member along a path into tissue. It should be notedthat the present invention is not limited by the type of driver usedwith the penetrating member feed mechanism. One suitable penetratingmember driver for use with the present invention is shown in FIG. 1.This is an embodiment of a solenoid type electromagnetic driver that iscapable of driving an iron core or slug mounted to the penetratingmember assembly using a direct current (DC) power supply. Theelectromagnetic driver includes a driver coil pack that is divided intothree separate coils along the path of the penetrating member, two endcoils and a middle coil. Direct current is alternated to the coils toadvance and retract the penetrating member. Although the driver coilpack is shown with three coils, any suitable number of coils may beused, for example, 4, 5, 6, 7 or more coils may be used.

Referring to the embodiment of FIG. 2, a stationary iron housing 10 maycontain the driver coil pack with a first coil 12 flanked by ironspacers 14 which concentrate the magnetic flux at the inner diametercreating magnetic poles. The inner insulating housing 16 isolates thepenetrating member 18 and iron core 20 from the coils and provides asmooth, low friction guide surface. The penetrating member guide 22further centers the penetrating member 18 and iron core 20. Thepenetrating member 18 is protracted and retracted by alternating thecurrent between the first coil 12, the middle coil, and the third coilto attract the iron core 20. Reversing the coil sequence and attractingthe core and penetrating member back into the housing retracts thepenetrating member. The penetrating member guide 22 also serves as astop for the iron core 20 mounted to the penetrating member 18.

As discussed above, analyte measurement devices which employ spring orcam driving methods have a symmetrical or nearly symmetrical actuationdisplacement and velocity profiles on the advancement and retraction ofthe penetrating member. In most of the available analyte measurementdevices, once the launch is initiated, the stored energy determines thevelocity profile until the energy is dissipated. Controlling impact,retraction velocity, and dwell time of the penetrating member within thetissue can be useful in order to achieve a high success rate whileaccommodating variations in skin properties and minimize pain.Advantages can be achieved by taking into account of the fact thattissue dwell time is related to the amount of skin deformation as thepenetrating member tries to puncture the surface of the skin andvariance in skin deformation from patient to patient based on skinhydration.

In this embodiment, the ability to control velocity and depth ofpenetration may be achieved by use of a controllable force driver wherefeedback is an integral part of driver control. Such drivers can controleither metal or polymeric penetrating members or any other type oftissue penetration element. The dynamic control of such a driver isillustrated in FIG. 3( c) which illustrates an embodiment of acontrolled displacement profile and FIG. 3( d) which illustrates anembodiment of a the controlled velocity profile. These are compared toFIGS. 3( a) and 3(b), which illustrate embodiments of displacement andvelocity profiles, respectively, of a harmonic spring/mass powereddriver. Reduced pain can be achieved by using impact velocities ofgreater than about 2 m/s entry of a tissue penetrating element, such asa lancet, into tissue. Other suitable embodiments of the penetratingmember driver are described in commonly assigned, copending U.S. patentapplication Ser. No. 10/127,395, (Attorney Docket No. 38187-2551) filedApr. 19, 2002 and previously incorporated herein.

FIG. 4 illustrates the operation of a feedback loop using a processor60. The processor 60 stores profiles 62 in non-volatile memory. A userinputs information 64 about the desired circumstances or parameters fora lancing event. The processor 60 selects a driver profile 62 from a setof alternative driver profiles that have been preprogrammed in theprocessor 60 based on typical or desired analyte measurement deviceperformance determined through testing at the factory or as programmedin by the operator. The processor 60 may customize by either scaling ormodifying the profile based on additional user input information 64.Once the processor has chosen and customized the profile, the processor60 is ready to modulate the power from the power supply 66 to thepenetrating member driver 68 through an amplifier 70. The processor 60may measure the location of the penetrating member 72 using a positionsensing mechanism 74 through an analog to digital converter 76 linearencoder or other such transducer. Examples of position sensingmechanisms have been described in the embodiments above and may be foundin the specification for commonly assigned, copending U.S. patentapplication Ser. No. 10/127,395, (Attorney Docket No. 38187-2551) filedApr. 19, 2002 and previously incorporated herein. The processor 60calculates the movement of the penetrating member by comparing theactual profile of the penetrating member to the predetermined profile.The processor 60 modulates the power to the penetrating member driver 68through a signal generator 78, which may control the amplifier 70 sothat the actual velocity profile of the penetrating member does notexceed the predetermined profile by more than a preset error limit. Theerror limit is the accuracy in the control of the penetrating member.

After the lancing event, the processor 60 can allow the user to rank theresults of the lancing event. The processor 60 stores these results andconstructs a database 80 for the individual user. Using the database 79,the processor 60 calculates the profile traits such as degree ofpainlessness, success rate, and blood volume for various profiles 62depending on user input information 64 to optimize the profile to theindividual user for subsequent lancing cycles. These profile traitsdepend on the characteristic phases of penetrating member advancementand retraction. The processor 60 uses these calculations to optimizeprofiles 62 for each user. In addition to user input information 64, aninternal clock allows storage in the database 79 of information such asthe time of day to generate a time stamp for the lancing event and thetime between lancing events to anticipate the user's diurnal needs. Thedatabase stores information and statistics for each user and eachprofile that particular user uses.

In addition to varying the profiles, the processor 60 can be used tocalculate the appropriate penetrating member diameter and geometrysuitable to realize the blood volume required by the user. For example,if the user requires about 1-5 μl volume of blood, the processor 60 mayselect a 200 micron diameter penetrating member to achieve theseresults. For each class of lancet, both diameter and lancet tipgeometry, is stored in the processor 60 to correspond with upper andlower limits of attainable blood volume based on the predetermineddisplacement and velocity profiles.

The analyte measurement device is capable of prompting the user forinformation at the beginning and the end of the lancing event to moreadequately suit the user. The goal is to either change to a differentprofile or modify an existing profile. Once the profile is set, theforce driving the penetrating member is varied during advancement andretraction to follow the profile. The method of lancing using theanalyte measurement device comprises selecting a profile, lancingaccording to the selected profile, determining lancing profile traitsfor each characteristic phase of the lancing cycle, and optimizingprofile traits for subsequent lancing events.

FIG. 5 illustrates an embodiment of an analyte measurement device, morespecifically, a lancing device 80 that includes a controllable driver 79coupled to a tissue penetration element. The lancing device 80 has aproximal end 81 and a distal end 82. At the distal end 82 is the tissuepenetration element in the form of a penetrating member 83, which iscoupled to an elongate coupler shaft 84 by a drive coupler 85. Theelongate coupler shaft 84 has a proximal end 86 and a distal end 87. Adriver coil pack 88 is disposed about the elongate coupler shaft 84proximal of the penetrating member 83. A position sensor 91 is disposedabout a proximal portion 92 (FIG. 6) of the elongate coupler shaft 84and an electrical conductor 94 electrically couples a processor 93 tothe position sensor 91. The elongate coupler shaft 84 driven by thedriver coil pack 88 controlled by the position sensor 91 and processor93 form the controllable driver, specifically, a controllableelectromagnetic driver.

Referring to FIG. 6, the lancing device 80 can be seen in more detail,in partial longitudinal section. The penetrating member 83 has aproximal end 95 and a distal end 96 with a sharpened point at the distalend 96 of the penetrating member 83 and a drive head 98 disposed at theproximal end 95 of the penetrating member 83. A penetrating member shaft101 is disposed between the drive head 98 and the sharpened point 97.The penetrating member shaft 101 may be comprised of stainless steel, orany other suitable material or alloy and have a transverse dimension ofabout 0.1 to about 0.4 mm. The penetrating member shaft may have alength of about 3 mm to about 50 mm, specifically, about 15 mm to about20 mm. The drive head 98 of the penetrating member 83 is an enlargedportion having a transverse dimension greater than a transversedimension of the penetrating member shaft 101 distal of the drive head98. This configuration allows the drive head 98 to be mechanicallycaptured by the drive coupler 85. The drive head 98 may have atransverse dimension of about 0.5 to about 2 mm.

A magnetic member 102 is secured to the elongate coupler shaft 84proximal of the drive coupler 85 on a distal portion 203 of the elongatecoupler shaft 84. The magnetic member 102 is a substantially cylindricalpiece of magnetic material having an axial lumen 104 extending thelength of the magnetic member 102. The magnetic member 102 has an outertransverse dimension that allows the magnetic member 102 to slide easilywithin an axial lumen 105 of a low friction, possibly lubricious,polymer guide tube 106 disposed within the driver coil pack 88. Themagnetic member 102 may have an outer transverse dimension of about 1.0to about 5.0 mm, specifically, about 2.3 to about 2.5 mm. The magneticmember 102 may have a length of about 3.0 to about 5.0 mm, specifically,about 4.7 to about 4.9 mm. The magnetic member 102 can be made from avariety of magnetic materials including ferrous metals such as ferroussteel, iron, ferrite, or the like. The magnetic member 102 may besecured to the distal portion 203 of the elongate coupler shaft 84 by avariety of methods including adhesive or epoxy bonding, welding,crimping or any other suitable method.

Proximal of the magnetic member 102, an optical encoder flag 106 issecured to the elongate coupler shaft 84. The optical encoder flag 106is configured to move within a slot in the position sensor 91. The slotmay have separation width of about 1.5 to about 2.0 mm. The opticalencoder flag 106 can have a length of about 14 to about 18 mm, a widthof about 3 to about 5 mm and a thickness of about 0.04 to about 0.06 mm.

The optical encoder flag 106 interacts with various optical beamsgenerated by LEDs disposed on or in the position sensor 91 in apredetermined manner. The interaction of the optical beams generated bythe LEDs of the position sensor 91 generates a signal that indicates thelongitudinal position of the optical flag 106 relative to the positionsensor 91 with a substantially high degree of resolution. The resolutionof the position sensor 91 may be about 200 to about 400 cycles per inch,specifically, about 350 to about 370 cycles per inch. The positionsensor 91 may have a speed response time (position/time resolution) of 0to about 120,000 Hz, where one dark and light stripe of the flagconstitutes one Hertz, or cycle per second. The position of the opticalencoder flag 206 relative to the magnetic member 102, driver coil pack88 and position sensor 91 is such that the position sensor 91 canprovide precise positional information about the penetrating member 83over the entire length of the penetrating member's power stroke.

An optical encoder that is suitable for the position sensor 91 is alinear optical incremental encoder, model HEDS 9200, manufactured byAgilent Technologies. The model HEDS 9200 may have a length of about 20to about 30 mm, a width of about 8 to about 12 mm, and a height of about9 to about 11 mm. Although the position sensor 91 illustrated is alinear optical incremental encoder, other suitable position sensorembodiments could be used, provided they posses the requisite positionalresolution and time response. The HEDS 9200 is a two channel devicewhere the channels are 90 degrees out of phase with each other. Thisresults in a resolution of four times the basic cycle of the flag. Thesequadrature outputs make it possible for the processor to determine thedirection of penetrating member travel. Other suitable position sensorsinclude capacitive encoders, analog reflective sensors, such as thereflective position sensor discussed above, and the like.

A coupler shaft guide 111 is disposed towards the proximal end 81 of thelancing device 80. The guide 111 has a guide lumen 112 disposed in theguide 111 to slidingly accept the proximal portion 92 of the elongatecoupler shaft 84. The guide 111 keeps the elongate coupler shaft 84centered horizontally and vertically in the slot 102 of the positionsensor 91.

As shown in FIGS. 7 and 8, a plurality of penetrating members 214 can bein a disposable member 222 that is placed in a housing of the analytemeasurement device. A plurality of analyte detecting members 216 arealso included. Each of an analyte detecting member 16 is coupled to apenetrating member 214. A sterility barrier 220 is configured to providesterile environments for the plurality of penetrating members 214. Thesterility barrier 220 can be made of a variety of materials includingbut not limited to, a metallic foil or other seal materials and may beof a tensile strength and other quality that may provide a sealed,sterile environment until the sterility barrier 220 is penetrated by apenetrating device 214, providing a preselected or selected amount offorce to open the sealed, sterile environment.

The sterility barrier 220 can be a planar material that is adhered to asurface of the disposable device 222. Depending on the orientation ofthe disposable device 222, the sterility barrier 220 can be on the topsurface, side surface, bottom surface, or other positioned surface ofthe disposable device 222.

The plurality of analyte detecting members 216 can be supported on ascaffolding 224. The scaffolding 224 can be attached to a bottom surfaceof the disposable device 222. The scaffolding 224 can be made of amaterial such as, but not limited to, a polymer, a foil, and the like.The scaffolding 224 can hold a plurality of analyte detecting members216, such as but not limited to, about 10-50, 50-100, or othercombinations of analyte detecting members 216. This facilitates theassembly and integration of analyte detecting members 216 withdisposable device 222. These analyte detecting members 216 can enable anintegrated body fluid sampling system where the penetrating members 214create a wound tract in a target tissue, which expresses body fluid thatflows into the disposable device 222 for analyte detection by at leastone of the analyte detecting members 216.

In one embodiment, many analyte detecting members 216 can be printedonto a single scaffolding 224 which is then adhered to the disposabledevice 222 to facilitate manufacturing and simplify assembly. Theanalyte detecting members 216 can be electrochemical in nature. Theanalyte detecting members 216 can further contain enzymes, dyes, orother detectors which react when exposed to the desired analyte.Additionally, the analyte detecting members 216 can comprise of clearoptical windows that allow light to pass into the body fluid for analyteanalysis. The number, location, and type of analyte detecting member 216can be varied as desired, based in part on the design of the disposabledevice 222, number of analytes to be measured, the need for analytedetecting member calibration, and the sensitivity of the analytedetecting members 216. Wicking elements, capillary tube or other deviceson the disposable device 222 can be provided to allow body fluid to flowfrom the disposable device 222 to the analyte detecting members 216 foranalysis. In other configurations, the analyte detecting members 216 canbe printed, formed, or otherwise located directly in the disposabledevice 222.

The disposable device 222 can include a plurality of cavities 226. Eachpenetrating member 214 may be contained in a cavity 226 in thedisposable device 222 with its sharpened end facing radially outward andmay be in the same plane as that of the disposable device 222. Thecavity 226 may be molded, pressed, forged, or otherwise formed in thedisposable device 222. Although not limited in this manner, the ends ofthe cavities 226 may be divided into individual fingers (such as one foreach cavity) on the outer periphery of the disposable device 222. Theparticular shape of each cavity 226 may be designed to suit the size orshape of the penetrating member therein or the amount of space desiredfor placement of the analyte detecting members 216. For example and notlimitation, the cavity 226 may have a V-shaped cross-section, a U-shapedcross-section, C-shaped cross-section, a multi-level cross section orthe other cross-sections. The opening through which a penetrating member214 may exit to penetrate tissue may also have a variety of shapes, suchas but not limited to, a circular opening, a square or rectangularopening, a U-shaped opening, a narrow opening that only allows thepenetrating member 214 to pass, an opening with more clearance on thesides, a slit, and the like.

The use of the sterility barrier 220 can facilitate the manufacture ofdisposable device 222. For example, a single sterility barrier 220 canbe adhered, attached, or otherwise coupled to the disposable device 222to seal many of the cavities 226 at one time. A sheet of analytedetecting members 216 can also be adhered, attached, or otherwisecoupled to the disposable device 222 to provide many analyte detectingmembers 216 on or in the disposable device 222 at one time. Duringmanufacturing of one embodiment of the present invention, the disposabledevice 222 can be loaded with penetrating members 214, sealed withsterility barrier 220 and a temporary layer (not shown) on the bottomwhere scaffolding 224 would later go, to provide a sealed environmentfor the penetrating members 214. This assembly with the temporary bottomlayer is then taken to be sterilized. After sterilization, the assemblyis taken to a clean room (or it can already be in a clear room orequivalent environment) where the temporary bottom layer is removed andthe scaffolding 224 with analyte detecting members 216 is coupled to thedisposable device 222. This process allows for the sterile assembly ofthe disposable device 222 with the penetrating members 214 usingprocesses and/or temperatures that can degrade the accuracy orfunctionality of the analyte detecting members 216 on the scaffolding224.

In some embodiments, more than one sterility barrier 220 can be used toseal the cavities 226. As examples of some embodiments, multiple layerscan be placed over each cavity 226, half or some selected portion of thecavities 226 can be sealed with one layer with the other half orselected portion of the cavities sealed with another sheet or layer,different shaped cavities 226 can use different seal layer, or the like.The sterility barrier 220 can have different physical properties, suchas those covering the penetrating members 214 near the end of thedisposable device 222 can have a different color such as red to indicateto the user (if visually inspectable) that the user is down to say 10,5, or other number of penetrating members before the cartridge should bechanged out.

After actuation, the penetrating member 214 is returned into thedisposable device 222 and is held therein in a manner so that it is notable to be used again. By way of example and not limitation, a usedpenetrating member 214 may be returned into the disposable member 222and held by a launcher in position until the next lancing event. At thetime of the next lancing, the launcher may disengage the usedpenetrating member with the disposable device 222 turned or indexed tothe next clean penetrating member 214 such that the cavity 226 holdingthe used penetrating member is positioned so that it is not accessibleto the user (i.e. turn away from a penetrating member exit opening). Insome embodiments, the tip of a used penetrating member 214 may be driveninto a protective stop that hold the penetrating member in place afteruse. The disposable device 222 is replaceable with a new disposabledevice 222 once all the penetrating members 214 have been used or atsuch other time or condition as deemed desirable by the user.

The disposable device 222 can provide sterile environments forpenetrating members 214 via the sterility barrier 220, seals, foils,covers, polymeric, or similar materials used to seal the cavities 226and provide enclosed areas for the penetrating members 214 to rest in.In one embodiment, sterility barrier 220 is applied to one surface ofthe disposable device 220. Each cavity 226 may be individually sealed ina manner such that the opening of one cavity 226 does not interfere withthe sterility in an adjacent or other cavity 226. Additionally, thedisposable device 222 can include a moisture barrier 228.

The plurality of penetrating members 214 can be at least partiallycontained in the cavities 226 of the disposable device 222. Thepenetrating members 214 are slidably movable to extend outward from thedisposable device 222 to penetrate tissue. The cavities 226 can eachhave a longitudinal opening that provides access to an elongate portionof the penetrating member 214. The sterility barrier 220 can cover thelongitudinal openings. The sterility barrier 220 can be configured to bemoved so that the elongate portion can be accessed by a gripper withouttouching the sterility barrier 220.

In one embodiment of the present invention, a method is provided ofanalyte measurement by a user using an analyte measurement device. Ananalyte measurement is provided with a plurality of penetrating membersand analyte sensors. Each analyte sensor is positioned in a samplechamber with a volume no greater than 1 μl. Each sample chamber has aworking electrode, reference electrode and a counter electrode. Theworking electrode has a conductor, an enzyme and a mediator. Apenetrating member and an unused analyte detecting member are presentedinto an active position. The following steps are then performed: (a) thepenetrating member is fired to prick the skin and bring a fluid sampleto the analyte detecting member, (b) the analyte level is measured, and(c) it takes no more than 10 seconds from the step of presenting thepenetrating members and unused analyte into the active position throughthe step of measuring the analyte level.

In other embodiments, steps (b) and (c) occur in less than 7 seconds,are performed without the user directly handling the penetrating memberto obtain a fresh penetrating member or load the penetrating member, areperformed without the user coding the analyte measurement device, andare performed without a separate step of apply blood to a analytedetection member after lancing. In certain embodiments, step (b) isperformed, without milking a wound., using at least one of a penetratingmember driver selected from, spring based, electromechanical based,magnetic driver based, and nanomuscle based, and with controlledvelocity and depth of penetration. In one embodiment, a time frompressing an on button of the device to lancing and measuring the analytelevel is no more than 10 seconds.

The conductor, mediator and enzyme can be in a single layer of theworking electrode. Each working electrode can include a layer that has aconductor, a reagent and the mediator. In one embodiment, the workingelectrode and the counter or reference electrode are coplanar.

The reagent interacts with glucose to produce an electroactive reactionproduct, and electroactive reaction product is correlated to aconcentration of glucose in a blood sample. The glucose level can thenbe displayed to the user and the value stored. In various embodiments,the detection of glucose occurs by, (i) applying a drop-detect potentialacross the working and counter or reference electrodes, (ii) applying adrop-detect potential across the working and counter or referenceelectrodes and recognizing a rise in current as an indication that theblood sample has been applied into the capillary chamber and (iii)reapplying a potential across the working and counter or referenceelectrodes after a delay period during which no potential is applied.

The application of blood to an analyte detection member during lancingcan occur without removal and disposal of penetrating members from theanalyte measurement device.

In another embodiment of the present invention, an analyte measurementis provided with a plurality of penetrating members and analyte sensors.Each analyte sensor is positioned in a sample chamber with a volume nogreater than 1 μl. Each sample chamber includes a working electrode,reference electrode and a counter electrode. The working electrode has aconductor, an enzyme and a mediator. The following steps are thenperformed, (a) a decision is made to test, (b) a penetrating member andan unused analyte detecting member are presented into an activeposition, (c) the penetrating member is fired to prick the skin andbring a fluid sample to the analyte detecting member and (d) the analytelevel is measured. Steps (a) through (d) occur in no more than 1 minute.In other embodiments, steps (a) through (d) occur in no more than 30seconds, and steps (a) through (d) occur in no more than 15 seconds,steps (a) through (d) occur in no more than 10 seconds.

In another embodiment of the present invention, the following steps areperformed. (a) a penetrating member and unused analyte detecting memberof the analyte measurement device are presented into an active positionby rotating the disposable device to align in an active position, sealscovering the penetrating member and analyte detecting member are thenremoved, (b) The penetrating member is fired to prick the skin using adriver to advance and retract from the skin to create a wound from whichbody fluid expresses, (c) a fluid sample is brought to the analytedetecting member by providing a sample capture structure positioned tocontact body fluid expressed from the wound, and (d) the analyte levelsare then measured. Steps (a) through (d) are completed in no more than10 seconds. In one embodiment, the time from pressing an on button ofthe device to lancing and measuring the analyte level is no more than 10seconds.

In another embodiment of the present invention, a disposable biosensortest strip includes a plurality of penetrating members. Each penetratingmember is associated with a capillary chamber that has a depth suitablefor capillary flow of blood and holds a volume of less than about 1.0 μlof the blood sample. A working electrode and a counter or referenceelectrode are disposed within the capillary chamber. A reagent isproximal to or in contact with at least the working electrode. Thereagent includes an enzyme and a mediator. The reagent reacts withglucose to produce an electroactive reaction product.

A blood sample, containing glucose, is applied into the capillarychamber. The capillary chamber directs capillary flow of the bloodsample into contact with the reagent to cause the blood sample to atleast partially solubilize or hydrate the reagent. The blood sample isdetected in the capillary chamber. The electroactive reaction product iselectro-oxidized or electro-reduced at the working electrode. Within 10seconds after detecting, a determination is made of glucoseconcentration and a readout of the measurement is provided. The glucosedetermination is made by correlating the electro-oxidized orelectro-reduced electroactive reaction product to the concentration ofglucose in the blood sample.

In one embodiment, the test strip has a bottom substrate, a spacinglayer, and a top substrate. The spacing layer has an openingcorresponding to the capillary chamber. The spacing layer substantiallydefines the depth of the capillary chamber. In one embodiment, the teststrip is a counter electrode and in the reagent is located proximal toor in contact with the working and counter electrodes.

In one embodiment, detection of glucose is achieved by applying adose-detect potential between the working and counter or referenceelectrodes. A rise in current indicates that the sample has beensupplied to the capillary chamber. In one embodiment, a potential of100-500 mV is applied across the working electrode and the counter orreference electrodes.

In various embodiments, (i) the reagent is supplied in a sufficientlysmall amount as to be solubilized or hydrated in a time sufficient toallow said determining and providing a readout of the glucoseconcentration in the sample within 10 seconds after said detecting, (ii)a mediator is provided in its oxidized form, (iii) the mediator reactssufficiently rapidly as to allow said determining and providing areadout of the glucose concentration in the sample within 10 secondsafter the detecting step and (iv) the reagent is provided in asufficiently small amount as to be solubilized or hydrated in a timesufficient to allow said determining and providing a readout of theglucose concentration in the sample within 10 seconds after thedetecting step.

In various embodiments, the test strip can have, (i) a bottom substrate,a spacing layer, and a top substrate, the spacing layer having anopening corresponding to the capillary chamber, the spacing layersubstantially defining the depth of the capillary chamber, (ii) a ventcommunicating with the capillary chamber to facilitate flow of thesample into the capillary chamber, (iii) a bottom substrate, a spacinglayer, and a top substrate, the spacing layer having an openingcorresponding to the capillary chamber, the spacing layer substantiallydefining the depth of the capillary chamber, (iv) an elongated geometrywith two opposed sides, the spacing layer comprising spaced-apart firstand second portions defining a capillary chamber extending between andopening at the two opposed sides, (v) a vent communicating with thecapillary chamber to facilitate flow of the sample into the capillarychamber, (vi) an elongated geometry with two opposed sides, the spacinglayer comprising spaced-apart first and second portions defining acapillary chamber extending between and opening at the two opposed sidesand (vii) a counter electrode, and in which the reagent is locatedproximal to or in contact with the working and counter electrodes.

In various embodiments, the capillary chamber holds a volume, (i) ofless than about 0.4 μl, (ii) of between about 0.25 μl and about 0.4 μl,(iii) of less than about 0.4 μl (iv) between about 0.25 μl and about0.4, (v) of about 600 nL, (vi) of between 0.25 μl and 0.4 μl (vii) ofabout 400 nL and (viii) of about 300 nL. The capillary chamber can havea depth of about 25 to 200 μm.

In various embodiments, a readout of the glucose concentration is madeabout, (i) 8 seconds after detecting, (ii) 3.5 to about 8 seconds afterdetecting, (iii) 4 seconds after detecting and (iv) 3 seconds afterdetecting. In one embodiment, the test strip, timing the reaction andanalysis of the blood sample are automatic to, (i) detect the bloodsample in the capillary chamber, (ii) electrooxidize the electroactivereaction product, and (iii) determine and provide a readout of theglucose concentration within 10 seconds of said detecting.

In one embodiment, the detection off glucose includes, applying adose-detect potential between the working and counter or referenceelectrodes, and then recognizing a rise in current as an indication thatthe sample has been supplied to the capillary chamber. In anotherembodiment, the electroactive reaction product is capable of beingelectrooxidized or electroreduced at the working electrode, and thedetermining of the glucose measures the amount of electroactive reactionproduct electrooxidized or electroreduced and then correlates the amountof electrooxidized or electroreduced electroactive reaction product tothe concentration of glucose in the blood sample.

In another embodiment of the present invention, a method of determiningthe concentration of glucose in a blood sample provides a disposablebiosensor test strip and a plurality of penetrating members. Eachpenetrating member is associated with a capillary chamber that has adepth suitable for capillary flow of blood and holds a volume of lessthan about 1.0 μl of the blood sample. A working electrode, and acounter or reference electrode, are disposed within the capillarychamber. A reagent is proximal to or in contact with at least theworking electrode. The reagent includes an enzyme and a mediator. Thereagent reacts with glucose to produce an electroactive reactionproduct.

A blood sample containing glucose is applied into the capillary chamber.The capillary chamber directs capillary flow of the blood sample intocontact with the reagent, causing the blood sample to at least partiallysolubilize or hydrate the reagent. The blood sample is detected in thecapillary chamber. The electroactive reaction product is electrooxidedat the working electrode. Within 10 seconds after detection, a readoutof the glucose concentration in the blood sample is provided. Detectionis made by correlating the electrooxidized electroactive reactionproduct to the concentration of glucose in the blood sample.

In one embodiment, the reagent is dry, and the capillary chamber directscapillary flow of the blood sample into contact with the dry reagent tocause the blood sample to at least partially solubilize or hydrate thedry reagent. The reagent can be a reagent that is applied wet and driedof solvent.

The reagent can be applied in a sufficiently small amount in order to besolubilized or hydrated in a time that is sufficiently fast to allow thedetermination and readout of the glucose concentration in the bloodsample within 10 seconds of the detection. In one embodiment, themediator reacts sufficiently rapid to provide a determination andreadout of glucose concentration in the blood sample within 10 secondsof said detection. The mediator can be readily reversible.

While the invention has been described and illustrated with reference tocertain particular embodiments thereof, those skilled in the art willappreciate that various adaptations, changes, modifications,substitutions, deletions, or additions of procedures and protocols maybe made without departing from the spirit and scope of the invention.For example, with any of the above embodiments, the shield or otherpunch may be adapted for use with other cartridges disclosed herein orin related applications. With any of the above embodiments, the methodstime may be measured from when the user touches the carrying case ortouches the housing (if the device is not being stored in a carryingcase).

The publications discussed or cited herein are provided solely for theirdisclosure prior to the filing date of the present application. Nothingherein is to be construed as an admission that the present invention isnot entitled to antedate such publication by virtue of prior invention.Further, the dates of publication provided may be different from theactual publication dates which may need to be independently confirmed.All publications mentioned herein are incorporated herein by referenceto disclose and describe the structures and/or methods in connectionwith which the publications are cited.

Expected variations or differences in the results are contemplated inaccordance with the objects and practices of the present invention. Itis intended, therefore, that the invention be defined by the scope ofthe claims which follow and that such claims be interpreted as broadlyas is reasonable.

1. A method of determining the concentration of glucose in a bloodsample, comprising: providing a disposable biosensor test stripincluding a plurality of penetrating members, each of a penetratingmember associated with a capillary chamber having a depth suitable forcapillary flow of blood and holding a volume of less than about 1.0 μlof the blood sample, a working electrode and a counter or referenceelectrode disposed within the capillary chamber, and a reagent proximalto or in contact with at least the working electrode, the reagentincluding an enzyme and a mediator, the reagent reacting with glucose toproduce an electroactive reaction product; applying a blood samplecontaining glucose into the capillary chamber, the capillary chamberdirecting capillary flow of the blood sample into contact with thereagent to cause the blood sample to at least partially solubilize orhydrate the reagent; detecting the blood sample in the capillarychamber; and electrooxidizing or electroreducing the electroactivereaction product at the working electrode; and within 10 seconds aftersaid detecting, determining and providing a readout of the glucoseconcentration in the blood sample, said determining comprisingcorrelating the electrooxidized or electroreduced electroactive reactionproduct to the concentration of glucose in the blood sample.
 2. Themethod of claim 1 in which said detecting comprises applying adose-detect potential between the working and counter or referenceelectrodes, and recognizing a rise in current as an indication that thesample has been supplied to the capillary chamber.
 3. The method ofclaim 1 in which the test strip includes a vent communicating with thecapillary chamber to facilitate flow of the sample into the capillarychamber.
 4. The method of claim 1 in which said providing comprisesproviding the reagent in a sufficiently small amount as to besolubilized or hydrated in a time sufficient to allow said determiningand providing a readout of the glucose concentration in the samplewithin 10 seconds after said detecting.
 5. The method of claim 1 inwhich said providing comprises providing a test strip including a bottomsubstrate, a spacing layer, and a top substrate, the spacing layerhaving an opening corresponding to the capillary chamber, the spacinglayer substantially defining the depth of the capillary chamber.
 6. Themethod of claim 5 in which the test strip is elongated with two opposedsides, the spacing layer comprising spaced-apart first and secondportions defining a capillary chamber extending between and opening atthe two opposed sides.
 7. The method of claim 1 in which said providingcomprises providing a mediator in its oxidized form.
 8. The method ofclaim 7 in which the mediator reacts sufficiently rapidly as to allowsaid determining and providing a readout of the glucose concentration inthe sample within 10 seconds after said detecting.
 9. The method ofclaim 8 in which said providing comprises providing the reagent in asufficiently small amount as to be solubilized or hydrated in a timesufficient to allow said determining and providing a readout of theglucose concentration in the sample within 10 seconds after saiddetecting.
 10. The method of claim 9 in which the capillary chamberholds a volume of less than about 0.4 μl.
 11. The method of claim 10 inwhich the capillary chamber holds a volume of between about 0.25 μl andabout 0.4 μl.
 12. The method of claim 11 in which said detectingcomprises applying a dose-detect potential between the working andcounter or reference electrodes, and recognizing a rise in current as anindication that the sample has been supplied to the capillary chamber.13. The method of claim 12 in which the test strip includes a ventcommunicating with the capillary chamber to facilitate flow of thesample into the capillary chamber.
 14. The method of claim 13 in whichsaid providing comprises providing a test strip including a bottomsubstrate, a spacing layer, and a top substrate, the spacing layerhaving an opening corresponding to the capillary chamber, the spacinglayer substantially defining the depth of the capillary chamber.
 15. Themethod of claim 14 in which the test strip is elongated with two opposedsides, the spacing layer comprising spaced-apart first and secondportions defining a capillary chamber extending between and opening atthe two opposed sides.
 16. The method of claim 1 in which the capillarychamber holds a volume of less than about 0.4 μl.
 17. The method ofclaim 16 in which the capillary chamber holds a volume of between about0.25 μl and about 0.4 μl.
 18. The method of claim 1 in which saidelectroactive reaction product is capable of being electrooxidized orelectroreduced at the working electrode, said determining comprisingmeasuring the amount of electroactive reaction product electrooxidizedor electroreduced, and correlating the amount of electrooxidized orelectroreduced electroactive reaction product to the concentration ofglucose in the blood sample.
 19. The method of claim 1 in which saidcapillary chamber has a depth of 25 200 μm.
 20. The method of claim 1including automatically operating the test strip and timing the reactionand analysis of the blood sample to detect the blood sample in thecapillary chamber, to electrooxidize the electroactive reaction product,and to determine and provide a readout of the glucose concentrationwithin 10 seconds of said detecting.
 21. The method of claim 1 in whichthe test strip comprises a counter electrode, and in which the reagentis located proximal to or in contact with the working and counterelectrodes.
 22. The method of claim 1 in which the capillary chamberholds a volume of about 600 nL.
 23. The method of claim 22 comprisingdetermining and providing a readout of the glucose concentration withinabout 5 seconds after said detecting.
 24. The method of claim 1 in whichthe capillary chamber holds a volume of between 0.25 μl and 0.4 μl . 25.The method of claim 24 comprising determining and providing a readout ofthe glucose concentration within about 5 seconds after said detecting.26. The method of claim 24 in which the capillary chamber holds a volumeof about 400 nL.
 27. The method of claim 26 comprising determining andproviding a readout of the glucose concentration within about 5 secondsafter said detecting.
 28. The method of claim 24 in which the capillarychamber holds a volume of about 300 nL.
 29. The method of claim 28comprising determining and providing a readout of the glucoseconcentration within about 5 seconds after said detecting.
 30. Themethod of claim 1 comprising determining and providing a readout of theglucose concentration within about 8 seconds of said detecting.
 31. Themethod of claim 30 comprising determining and providing a readout of theglucose concentration about 3.5 to about 8 seconds after said detecting.32. The method of claim 31 comprising determining and providing areadout of the glucose concentration within about 5 seconds of saiddetecting.
 33. The method of claim 32 comprising determining andproviding a readout of the glucose concentration within about 4 secondsof said detecting.
 34. The method of claim 31 comprising determining andproviding a readout of the glucose concentration about 5 seconds aftersaid detecting.
 35. The method of claim 31 comprising determining andproviding a readout of the glucose concentration about 4 seconds aftersaid detecting.
 36. A method of determining the concentration of glucosein a blood sample, comprising: providing a disposable biosensor teststrip and a plurality of penetrating members, each of a penetratingmember associated with a capillary chamber having a depth suitable forcapillary flow of blood and holding a volume of less than about 1.0 μlof the blood sample, a working electrode and a counter or referenceelectrode disposed within the capillary chamber, and a reagent proximalto or in contact with at least the working electrode, the reagentincluding an enzyme and a mediator, the reagent reacting with glucose toproduce an electroactive reaction product; applying a blood samplecontaining glucose into the capillary chamber, the capillary chamberdirecting capillary flow of the blood sample into contact with thereagent to cause the blood sample to at least partially solubilize orhydrate the reagent; detecting the blood sample in the capillarychamber; electrooxidizing the electroactive reaction product at theworking electrode; and within 10 seconds after said detecting,determining and providing a readout of the glucose concentration in theblood sample, said determining comprising correlating theelectrooxidized electroactive reaction product to the concentration ofglucose in the blood sample.
 37. The method of claim 36 in which thecapillary chamber holds a volume of about 600 nL.
 38. The method ofclaim 37 comprising determining and providing a readout of the glucoseconcentration within about 5 seconds after said detecting.
 39. Themethod of claim 36 in which the capillary chamber holds a volume ofbetween 0.25 μl and 0.4 μl.
 40. The method of claim 39 comprisingdetermining and providing a readout of the glucose concentration withinabout 5 seconds after said detecting.
 41. The method of claim 39 inwhich the capillary chamber holds a volume of about 400 nL.
 42. Themethod of claim 41 comprising determining and providing a readout of theglucose concentration within about 5 seconds after said detecting. 43.The method of claim 39 in which the capillary chamber holds a volume ofabout 300 nL.
 44. The method of claim 43 comprising determining andproviding a readout of the glucose concentration within about 5 secondsafter said detecting.
 45. The method of claim 36 comprising determiningand providing a readout of the glucose concentration within about 8seconds of said detecting.
 46. The method of claim 45 comprisingdetermining and providing a readout of the glucose concentration about3.5 to about 8 seconds after said detecting.
 47. The method of claim 46comprising determining and providing a readout of the glucoseconcentration within about 5 seconds of said detecting.
 48. The methodof claim 47 comprising determining and providing a readout of theglucose concentration within about 4 seconds of said detecting.
 49. Themethod of claim 46 comprising determining and providing a readout of theglucose concentration about 5 seconds after said detecting.
 50. Themethod of claim 46 comprising determining and providing a readout of theglucose concentration about 4 seconds after said detecting.
 51. Themethod of claim 36 in which the reagent is dry, and the capillarychamber directs capillary flow of the blood sample into contact with thedry reagent to cause the blood sample to at least partially solubilizeor hydrate the dry reagent.
 52. The method of claim 51 in which the dryreagent comprises a reagent that is applied wet and dried of solvent.53. The method of claim 36 in which the capillary chamber has a depth of25-200 μm.
 54. The method of claim 36 in which said providing comprisesproviding the reagent in a sufficiently small amount as to besolubilized or hydrated in a time sufficiently fast to allow saiddetermining and providing a readout of the glucose concentration in theblood sample within 10 seconds of said detecting.
 55. The method ofclaim 54 in which the mediator reacts sufficiently rapidly as to allowdetermining and providing a readout of the glucose concentration in theblood sample within 10 seconds of said detecting.
 56. The method ofclaim 55 in which the mediator is readily-reversible.
 57. The method ofclaim 36 including automatically operating the test strip and timing thereaction and analysis of the blood sample to detect the blood sample inthe capillary chamber, to electrooxidize the electroactive reactionproduct, and to determine and provide a readout of the glucoseconcentration within 10 seconds of said detecting.
 58. The method ofclaim 57 in which said automatically operating comprises connecting thetest strip to an external testing apparatus prior to said detecting, thetesting apparatus automatically detecting the blood sample in thecapillary chamber, electrooxidizing the electroactive reaction product,determining the glucose concentration, and providing a readout of theglucose concentration within 10 seconds of said detecting.
 59. Themethod of claim 36 in which the working electrode and the counter orreference electrode are coplanar.
 60. The method of claim 36 comprisingmeasuring the current and correlating the measured current to theglucose concentration.
 61. The method of claim 36 in which saiddetecting comprises applying a drop-detect potential across the workingand counter or reference electrodes.
 62. The method of claim 61 in whichsaid detecting comprises applying a drop-detect potential across theworking and counter or reference electrodes prior to and separate fromsaid determining.
 63. The method of claim 62 in which said detectingcomprises applying a drop-detect potential across the working andcounter or reference electrodes and recognizing a rise in current as anindication that the blood sample has been applied into the capillarychamber.
 64. The method of claim 62 which includes reapplying apotential across the working and counter or reference electrodes, aftera delay period during which no potential is applied, to electrooxidizethe electroactive reaction product at the working electrode.
 65. Themethod of claim 36 in which said providing comprises providing a teststrip including a bottom substrate, a spacing layer, and a topsubstrate, the spacing layer having an opening corresponding to thecapillary chamber, the spacing layer substantially defining the depth ofthe capillary chamber.
 66. The method of claim 36 in which said reactingproduces a reduced form of the mediator.
 67. The method of claim 36comprising measuring the amount of the electrooxidized electroactivereaction product and correlating the amount to the concentration ofglucose in the blood sample.
 68. The method of claim 36 comprisingapplying a potential of 100-500 mV across the working electrode and thecounter or reference electrodes.
 69. The method of claim 36 in which thetest strip comprises a counter electrode, and in which the reagent islocated proximal to or in contact with the working and counterelectrodes.